commit 6df407bc07cea62a53772325c60de06a3c869dd2
author Jason A. Donenfeld <Jason@zx2c4.com> Sat Jun 08 22:13:16 2019 +0200
committer Jason Donenfeld <Jason@zx2c4.com> Sun Jun 09 07:43:00 2019 +0000
tree 6d05802f22de75c3b2dd3d3813c0c03df3686037
parent 5b15430b70e38eb7f9c844f97c25f25a246d5c63

windows: correct types and error values of internal GUID handling

This corrects the Windows int type to be the more correct int32 Go
analog, as well as not using GetLastError() for the error value of the
GUID string parsing function.

Change-Id: I9716f991ef649f7d299295e3f4e75d3986ec3a74
Reviewed-on: https://go-review.googlesource.com/c/sys/+/181397
Run-TryBot: Jason Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

windows/syscall_windows.go

diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index 74b72a0..1d1170a 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -288,8 +288,8 @@
 //sys	SetVolumeLabel(rootPathName *uint16, volumeName *uint16) (err error) = SetVolumeLabelW
 //sys	SetVolumeMountPoint(volumeMountPoint *uint16, volumeName *uint16) (err error) = SetVolumeMountPointW
 //sys	MessageBox(hwnd Handle, text *uint16, caption *uint16, boxtype uint32) (ret int32, err error) [failretval==0] = user32.MessageBoxW
-//sys	clsidFromString(lpsz *uint16, pclsid *GUID) (err error) [failretval!=0] = ole32.CLSIDFromString
-//sys	stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int) (chars int) = ole32.StringFromGUID2
+//sys	clsidFromString(lpsz *uint16, pclsid *GUID) (ret error) = ole32.CLSIDFromString
+//sys	stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int32) (chars int32) = ole32.StringFromGUID2
 //sys	coCreateGuid(pguid *GUID) (ret error) = ole32.CoCreateGuid
 
 // syscall interface implementation for other packages
@@ -1276,7 +1276,7 @@
 // in the form of "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}".
 func (guid GUID) String() string {
 	var str [100]uint16
-	chars := stringFromGUID2(&guid, &str[0], len(str))
+	chars := stringFromGUID2(&guid, &str[0], int32(len(str)))
 	if chars <= 1 {
 		return ""
 	}

windows/syscall_windows_test.go

diff --git a/windows/syscall_windows_test.go b/windows/syscall_windows_test.go
index b157625..9f78e2d 100644
--- a/windows/syscall_windows_test.go
+++ b/windows/syscall_windows_test.go
@@ -191,4 +191,8 @@
 	if guid2 != guid {
 		t.Fatalf("Did not parse string back to original GUID = %q; want %q", guid2, guid)
 	}
+	_, err = windows.GUIDFromString("not-a-real-guid")
+	if err != syscall.Errno(windows.CO_E_CLASSSTRING) {
+		t.Fatalf("Bad GUID string error = %v; want CO_E_CLASSSTRING", err)
+	}
 }

windows/zsyscall_windows.go

diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index f37d7d4..6c35b90 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -2436,21 +2436,17 @@
 	return
 }
 
-func clsidFromString(lpsz *uint16, pclsid *GUID) (err error) {
-	r1, _, e1 := syscall.Syscall(procCLSIDFromString.Addr(), 2, uintptr(unsafe.Pointer(lpsz)), uintptr(unsafe.Pointer(pclsid)), 0)
-	if r1 != 0 {
-		if e1 != 0 {
-			err = errnoErr(e1)
-		} else {
-			err = syscall.EINVAL
-		}
+func clsidFromString(lpsz *uint16, pclsid *GUID) (ret error) {
+	r0, _, _ := syscall.Syscall(procCLSIDFromString.Addr(), 2, uintptr(unsafe.Pointer(lpsz)), uintptr(unsafe.Pointer(pclsid)), 0)
+	if r0 != 0 {
+		ret = syscall.Errno(r0)
 	}
 	return
 }
 
-func stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int) (chars int) {
+func stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int32) (chars int32) {
 	r0, _, _ := syscall.Syscall(procStringFromGUID2.Addr(), 3, uintptr(unsafe.Pointer(rguid)), uintptr(unsafe.Pointer(lpsz)), uintptr(cchMax))
-	chars = int(r0)
+	chars = int32(r0)
 	return
 }